1. Field of the Invention
The present invention relates to an amending circuit, and more particularly, to an amending circuit capable of switching a mouse into different detecting modes.
2. Description of the Prior Art
An internal control circuit of the conventional mouse has eight pins to respectively control the button, the roller and the indicating light source. The button and the roller can be electrically connected with the same pin to decrease amounts of the pin and to economize material cost of the 6-pin mouse. As the single pin is shared among the button, the roller and the indicating light source, reference voltages of the roller and the button are unstable and cannot accurately design the related control circuit while a loading resistance of the indicating light source is an unknown value (or the resistance is uncertain due to low quality of the loading resistor). Therefore, design of an amend circuit capable of automatically amending reference voltages of the roller and the button which are coupled to the same pin according to the related loading resistance is an important issue in the mouse industry.